Since an electronic device has various sophisticated electronic components inside, a cover plate or a casing is necessary to protect the internal electronic components. In the content disclosed in prior art, metal is the main material as cover plates. However, metal has the disadvantages of being susceptive to oxidation and shielding electromagnetic signals; some cover plates made of glass are also disclosed in prior art. For example, Chinese patent CN101508524A discloses a chemically strengthened glass, and the properties thereof such as the drop resistance and the fracture toughness are difficult to meet actual demands.
A glass-ceramic is a material that precipitates crystals inside the glass through heat-treating the glass. With the crystals dispersed inside the glass-ceramic, the glass-ceramic has physical values that cannot be obtained in the glass. For instance, the mechanical strengths such as young modulus and fracture toughness, etching characteristics against an acid or alkaline medicine solution, thermal properties such as thermal expansion coefficient, increase or disappearance of the glass transition temperature, and the like. Glass-ceramic has higher mechanical properties, and due to the crystals formed in the glass-ceramic, the glass-ceramic has obvious advantages over the ordinary glass in some properties such as bending resistance and wear resistance.
Based on the aforementioned factors, the inventors expect to develop a glass-ceramic having excellent mechanical properties and being suitable for the electronic devices through extensive experiments.